Written by Amy Woodyatt, CNNLondon

A “treasure trove” of previously unseen writings by “The Lord of the Rings” author J.R.R. Tolkien exploring Middle-earth will be published in June 2021, publisher HarperCollins has confirmed.

The collection, titled “The Nature of Middle-earth,” will “transport readers back to the world of ‘The Silmarillion,’ ‘Unfinished Tales’ and ‘The Lord of the Rings,'” the publisher said Thursday.

Tolkien’s beloved books “The Lord of the Rings” and “The Hobbit” are international bestsellers in more than 70 languages, and have been turned into multibillion-dollar movie trilogies.

“It is well known that J.R.R. Tolkien published ‘The Hobbit’ in1937 and ‘The Lord of the Rings’ in 1954-5. What may be less known is that he continued to write about Middle-earth in the decades that followed, right up until the years before his death in 1973,” Chris Smith, HarperCollins deputy publishing director, said in a statement.

"The Nature of Middle-earth" will be published in June 2021.

“The Nature of Middle-earth” will be published in June 2021. Credit: HarperCollins

“For him, Middle-earth was part of an entire world to be explored, and the writings in ‘The Nature of Middle-earth’ reveal the journeys that he took as he sought to better understand his unique creation,” Smith added.

The collection will explore a range of fantastical themes, including Elvish immortality and reincarnation and the geography of the settings of some of Tolkien’s most famed fantasy epics, Smith added.

“This new collection is a veritable treasure-trove offering readers a chance to peer over Professor Tolkien’s shoulder at the very moment of discovery: and on every page, Middle-earth is once again brought to extraordinary life,” he said.

The collection will be edited by Carl F. Hostetter, a leading Tolkien expert, the head of the Elvish Linguistic Fellowship, and a NASA computer engineer.

The book will be available on June 24, and will be published by HarperCollins in the UK and by Houghton Mifflin Harcourt in North America.